Critical Clearing Time Enhancement of Droop-Controlled Grid-Forming Inverters with Adaptive Function-Based Parameters

TL;DR

This paper introduces an adaptive control method for grid-forming inverters that autonomously adjusts parameters to improve transient stability and maximize critical clearing time, validated through simulations.

Contribution

It proposes a novel adaptive function-based parameter adjustment for droop-controlled GFM inverters to enhance transient stability and critical clearing time.

Findings

Significant increase in critical clearing time demonstrated in simulations

Adaptive method outperforms existing CCT enhancement techniques

Improved transient stability under various disturbance scenarios

Abstract

With the increasing penetration of renewable energy sources, grid-forming (GFM) inverters are becoming essential for voltage and frequency regulation. However, the transient stability of GFM inverter is critically affected by the current limiters that are embedded with the standard control schemes. This paper proposes a novel adaptive function to enhance the transient stability of droop-controlled GFM inverters. The proposed method autonomously adjusts the active power reference and the droop gain based on the terminal voltage of the inverter. Also, the acceleration of the phase angle is prevented, leading to the maximization of critical clearing time (CCT). The proposed method is benchmarked against two state-of-the-art GFM inverter CCT enhancement methods. Effectiveness of the proposed method is validated through electromagnetic transient (EMT) simulations in MATLAB/Simulink\textsuperscript{\textregistered}.